Magnetocrystalline origin of the perpendicular magnetic anisotropy in Ga-poor FeGa thin films

Abstract

In this work we have investigated the influence of Ar sputtering pressure (PAr) in the magnetic properties of polycrystalline sputtered Fe0.89Ga0.11 thin films. The structural characterization shows that the samples are composed by several fiber-like crystallographic textures in which the fiber axis is always along the growth direction, whereas their portion weights evolve with PAr during the sputtering deposition. Magnetometry and ferromagnetic resonance (FMR) experiments evidence the existence of a perpendicular magnetic anisotropy (PMA) that increases systematically for increasing PAr. By proposing a model that takes into account the interfacial, magnetoelastic and magnetocrystalline contributions to the magnetic free energy, we find that the magnetocrystalline one appears as the main responsible of the increasing PMA. The PMA values estimated from the model predict satisfactorily the experimental values obtained from FMR.